The fish gill is a multipurpose organ that, in addition to providing for aquatic gas exchange, plays dominant roles in osmotic and ionic regulation, acid-base regulation, and excretion of nitrogenous wastes Thus, despite the fact that all fish groups have functional kidneys, the gill epithelium is the site of many processes that are mediated by renal epithelia in terrestrial vertebrates Indeed, many of the pathways that mediate these processes in mammalian renal epithelial are expressed in the gill, and many of the extrinsic and intrinsic modulators of these processes are also found in fish endocrine tissues and the gill itself The basic patterns of gill physiology were outlined over a half century ago, but modern immunological and molecular techniques are bringing new insights into this complicated system Nevertheless, substantial questions about the evolution of these mechanisms and control remain

https://people.clas.ufl.edu/devans/files/PRVGill.pdf

The Multifunctional Fish Gill: Dominant Site of Gas Exchange, Osmoregulation, Acid-Base Regulation, and Excretion of Nitrogenous Waste

https://digital.csic.es/bitstream/10261/63157/4/Gomez-Guillen-collagenreview_CSIC.pdf

Functional and bioactive properties of collagen and gelatin from alternative sources: A review

Seaweed is more than the wrap that keeps rice together in sushi. Seaweed biomass is already used for a wide range of other products in food, including stabilising agents. Biorefineries with seaweed as feedstock are attracting worldwide interest and include low-volume, high value-added products and vice versa. Scientific research on bioactive compounds in seaweed usually takes place on just a few species and compounds. This paper reviews worldwide research on bioactive compounds, mainly of nine genera or species of seaweed, which are also available in European temperate Atlantic waters, i.e. Laminaria sp., Fucus sp., Ascophyllum nodosum, Chondrus crispus, Porphyra sp., Ulva sp., Sargassum sp., Gracilaria sp. and Palmaria palmata. In addition, Undaria pinnatifida is included in this review as this is globally one of the most commonly produced, investigated and available species. Fewer examples of other species abundant worldwide have also been included. This review will supply fundamental information for biorefineries in Atlantic Europe using seaweed as feedstock. Preliminary selection of one or several candidate seaweed species will be possible based on the summary tables and previous research described in this review. This applies either to the choice of high value-added bioactive products to be exploited in an available species or to the choice of seaweed species when a bioactive compound is desired. Data are presented in tables with species, effect and test organism (if present) with examples of uses to enhance comparisons. In addition, scientific experiments performed on seaweed used as animal feed are presented, and EU, US and Japanese legislation on functional foods is reviewed.

Bioactive compounds in seaweed: functional food applications and legislation

Despite an increased knowledge of microbial xylanolytic systems in the past few years, further studies are required to achieve a complete understanding of the mechanism of xylan degradation by microorganisms and their enzymes. The enzyme system used by microbes for the metabolism of xylan is the most important tool for investigating the use of the second most abundant polysaccharide (xylan) in nature. Recent studies on microbial xylanolytic systems have generally focussed on induction of enzyme production under different conditions, purification, characterization, molecular cloning and expression, and use of enzyme predominantly for pulp bleaching. Rationale approaches to achieve these goals require a detailed knowledge of the regulatory mechanism governing enzyme production. This review will focus on complex xylan structure and the microbial enzyme complex involved in its complete breakdown, studies on xylanase regulation and production and their potential industrial applications, with special reference to biobleaching.

Microbial xylanases and their industrial applications: a review.

Antioxidative peptides from food proteins: a review

Antioxidative activities of 28 synthetic peptides, which were designed based on an antioxidative peptide (Leu-Leu-Pro-His-His) derived from proteolytic digests of a soybean protein, against the peroxidation of linoleic acid in an aqueous system were measured by the ferric thiocyanate method. The results for the hydroperoxide levels derived from linoleic acid agreed with those obtained by reversed-phase high-performance liquid chromatography. The deletion of the C-terminal His decreased the activity, whereas the deletion of the N-terminal Leu had no effect. In the peptide sequence, His and Pro played important roles in the antioxidative activity and, among the peptides tested, Pro-His-His was the most antioxidative. The activity decreased on substitution of the second His with d-His. Introduction of Tyr to the positions of Pro or His did not increase the activities of the corresponding peptides. Antioxidative peptides showed synergistic effects with nonpeptidic antioxidants as observed in soybean protein h...

Antioxidant Activity of Designed Peptides Based on the Antioxidative Peptide Isolated from Digests of a Soybean Protein

The properties of 22 synthetic peptides containing histidine, which were designed on the basis of the antioxidative peptide (Leu-Leu-Pro-His-His) derived from proteolytic digests of a soybean protein, were examined with regard to their antioxidative activity against the peroxidation of linoleic acid and the scavenging effects on active oxygen and free radical species. The antioxidative activities of these peptides in an emulsion oxidation system using 2,2'-azobis(2-amidinopropane) dihydrochloride as a radical initiator correlated well within an aqueous system. Although the histidine-containing peptides had a quenching activity on singlet oxygen, they did not show antioxidative activity in an 2,2'-azobis(2,4-dimethylvaleronitrile)-induced oxidation system or scavenging effects on 1,1-diphenyl-2-picrylhydrazyl radical and superoxide. The metal-ion chelating activities and the hydrophobicities of these peptides showed no direct correlation with their antioxidative activities. Leu-Leu-Pro-His-His was modified with a hydroxyl radical in an aqueous ethanol system during the peroxidation of linoleic acid.

/pdf/antioxidative-properties-of-histidine-containing-peptides-2wwy05wdlv.pdf

Antioxidative Properties of Histidine-Containing Peptides Designed from Peptide Fragments Found in the Digests of a Soybean Protein

Protease hydrolyses of a soybean protein, beta-conglycinin (7S protein), yielded antioxidative activity against the peroxidation of linoleic acid in an aqueous system at pH 7.0. Six antioxidative peptides were isolated from the hydrolysate prepared with protease S by size exclusion chromatography and reversed-phase HPLC. The amino acid sequences of the peptides were determined using a gas-phase protein sequencer and electron spray mass spectrometry. The peptides were composed of 5-16 amino acid residues, including hydrophobic amino acids, valine or leucine, at the N-terminal positions, and proline, histidine, or tyrosine in the sequences.

Structural Analysis of Antioxidative Peptides from Soybean .beta.-Conglycinin

Two series of combinatorial tripeptide libraries were constructed, based on an antioxidative peptide isolated from a soybean protein hydrolysate. One was a library of 108 peptides containing either His or Tyr residues. Another was a library of 114 peptides related to Pro-His-His, which had been identified as an active core of the antioxidative peptide. The antioxidative properties of these libraries were examined by several methods, such as the antioxidative activity against the peroxidation of linoleic acid, the reducing activity, the radical scavenging activity, and the peroxynitrite scavenging activity. Two Tyr-containg tripeptides showed higher activities than those of two His-containing tripeptides in the peroxidation of linoleic acid. Tyr-His-Tyr showed a strong synergistic effects with phenolic antioxidants. However, the tripeptide had only marginal reducing activity and a moderate peroxynitrite scavenging activity. Cysteine-containing tripeptides showed the strong peroxynitrite scavenging activity. Change of either the N-terminus or C-terminus of Pro-His-His to other amino acid residues did not significantly alter their antioxidative activity. Tripeptides containing Trp or Tyr residues at the C-terminus had strong radical scavenging activities, but very weak peroxynitrite scavenging activity. The present results allow us to understand why protein digests have such a variety of antioxidative properties.

Antioxidative properties of tripeptide libraries prepared by the combinatorial chemistry.

Seven kinds of angiotensin I-converting enzyme (ACE) inhibitory peptides were isolated from the hydrolysates of wakame (Undaria pinnatifida) by Protease S “Amano” (from Bacillus stearothermophilus) by using three-step high-performance liquid chromatography (HPLC) on a reverse-phase column. These peptides were identified by amino acid composition analysis, sequence analysis, and liquid chromatography−mass spectrometry (LC−MS), as Val-Tyr (IC50 = 35.2 μM), Ile-Tyr (6.1 μM), Ala-Trp (18.8 μM), Phe-Tyr (42.3 μM), Val-Trp (3.3 μM), Ile-Trp (1.5 μM), and Leu-Trp (23.6 μM). These peptides have resistance against gastrointestinal proteases in vitro. Each peptide was determined to have an antihypertensive effect after a single oral administration in spontaneously hypertensive rats (SHR). Among them, the blood pressure significantly decreased by Val-Tyr, Ile-Tyr, Phe-Tyr, and Ile-Trp in a dose of 1 mg/kg of body weight (BW). The present study showed that antihypertensive effect in the hydrolysates of wakame by Prot...

Angiotensin I-Converting Enzyme Inhibitory Peptides Derived from Wakame (Undaria pinnatifida) and Their Antihypertensive Effect in Spontaneously Hypertensive Rats

Koji Muramoto

Papers

Antioxidant Activity of Designed Peptides Based on the Antioxidative Peptide Isolated from Digests of a Soybean Protein

Antioxidative Properties of Histidine-Containing Peptides Designed from Peptide Fragments Found in the Digests of a Soybean Protein

Structural Analysis of Antioxidative Peptides from Soybean .beta.-Conglycinin

Antioxidative properties of tripeptide libraries prepared by the combinatorial chemistry.

Angiotensin I-Converting Enzyme Inhibitory Peptides Derived from Wakame (Undaria pinnatifida) and Their Antihypertensive Effect in Spontaneously Hypertensive Rats